#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
void error_handling( char * msg );

int main( int argc, char * argv[])
{
    int sock;
    struct sockaddr_in send_adr;
    if ( 3 != argc) {
        printf(" Usage : %s <IP> <port>\n", argv[0] );
        exit( 1 );
    }

    sock = socket( PF_INET, SOCK_STREAM, 0);
    memset( &send_adr, 0, sizeof(send_adr) );
    send_adr.sin_family = AF_INET;
    send_adr.sin_addr.s_addr = inet_addr( argv[1] );
    send_adr.sin_port = htons( atoi(argv[2]));

    if (-1 == connect(sock, (struct sockaddr *) &send_adr, sizeof(send_adr))) {
        error_handling( "connect() error!");
    }

    write( sock, "123", 3);
    close( sock );


    return 0;
}
void error_handling( char * msg )
{
    fputs( msg, stderr );
    fputc( '\n', stderr );
    exit( 1 );
}